1. Field of the Invention
The present invention relates to a fan for sending air in which a rotor of a motor is arranged in an impeller cup.
2. Description of the Related Art
Bearing devices using fluid dynamic pressure (hereinafter referred to as a dynamic pressure bearing) are conventionally used for a spindle motor of a signal recording and reproducing device such as a hard disk drive.
These days, the signal recording and reproducing devices such as hard disk drives are installed in portable devices such as portable music players, and there is a great demand for a signal recording and reproducing device which has more storage capacity, and reduced thickness and dimensions. In order to reduce the thickness and the dimensions of the signal recording and reproducing device, it is desirable to reduce the thickness and dimensions of the spindle motor.
By reducing the thickness of the spindle motor, however, an axial height of the dynamic pressure bearing is reduced as well, thereby reducing resistance of the dynamic pressure bearing against an external force.